Monday saw a second day of South Korea-U.S. naval exercises in the East Sea, a show of force code-named "Invincible Spirit" in response to North Korea's sinking of the Navy corvette Cheonan in March. A day before the 57th anniversary of the armistice that halted the Korean War, the two allies conducted an anti-submarine drill, and a joint formation and mid-aid refueling drill in the air over the Korean Peninsula joined by F-22 stealth fighter jets. Unprecedentedly, the press were invited to watch the aerial drill over the nuclear-powered U.S. aircraft carrier George Washington in the East Sea and look at the F-22s or "Raptors" at Osan Air Base in Gyeonggi Province. Two of four F-22s from Kadena Air Base in Okinawa, Japan were shown combat-ready at a hangar of the 5th U.S. Reconnaissance Squadron at Osan that morning. It was the first time they have ever been open to the public here and have ever taken part in a joint South Korea-U.S. exercise. Lt. Gen. Jeffrey Remington, commander of the 7th U.S. Air Force, said that the deployment of F-22s for the drills demonstrates Washington's strong commitment to deter and defeat any provocative acts that threaten the stability of the Korean Peninsula and Northeast Asia. He said, "As with all of our combined air assets in theater, the F-22s stand ready to respond in the defense of the Republic of Korea." The air readiness exercise with the F-22 fighter jets "provides valuable combined training as well as demonstrates the resolve and support for our Republic of Korea allies," he added. The supersonic jet can launch precision strikes at strategic targets any place in North Korea 30 minutes to an hour after taking off from Kadena.